In recent years, card devices such as PC (Personal Computer) cards that fulfill functions as cards by being supplied with power have become popular (e.g., Patent literatures 1, 2, 3, and 4).
FIG. 8 is a diagram showing a state in which a card device 10 is inserted into a card slot 21 of a main body device 20 as one usage mode of a card device. FIG. 8 shows a case in which a single card device 10 is used. FIG. 9 is an external perspective view of the card device 10. The card device 10 includes a power supply connector (hereinafter referred to as an external connector 12) in an edge 11 located in an opening side 22 of the card slot 21 in a state in which the card device 10 is inserted into the card slot 21. A power supply cable 31 of an external power supply 30 provided outside the main body device 20 is connected to the external connector 12. Thus, the card device 10 is supplied with power.
FIG. 10 is a diagram showing a case in which a plurality of card devices 40 are used as another usage mode of the card device. A main body device 50 using the plurality of card devices 40 includes a back board part 53 for supplying power in a deepest side 52 of a card slot 51. FIG. 11 is an external perspective view of the card device 40 used in the main body device 50. This card device 40 includes a power supply connector (hereinafter referred to as a main body connector 42) in an edge 41 located in the deepest side 52 of the card slot 51 when the card device 40 is inserted into the card slot 51. When the card device 40 is inserted into the card slot 51, the main body connector 42 is connected to the back board part 53. When power is supplied from an external power supply 30 to a power supply unit 54, power is supplied from the back board part 53 of the main body device 50 to the main body connector 42, from which power is supplied to card device 40.
Patent literature 1 discloses a configuration to allow a host to use a card device that requires power larger than that supplied from the host. Patent literature 1 discloses the card device including a connector used for a connection with the host, and another power supply terminal to externally supply power to an internal circuit.
Patent literatures 2 and 3 each disclose a unit supplied with power from a backboard of a device. Patent literature 4 discloses an expansion board externally supplied with power.